What can a CT Scan show that an MRI cannot? Learn the similarities and differences in the two scans and how you can prepare for your scan . Key Takeaways: CT scans and MRIs serve distinct purposes in diagnosing and staging cancer. Noting the differences between CT Scans and MRIs can assist in the choice making, depending on various factors, including the specific disease or condition being assessed and individual patient situations given. Medical professionals carefully weigh the differences between CT Scans and MRIs along with the benefits and risks to determine the most appropriate imaging approach for optimal patient care. Both are imaging procedures. CT scans use X-rays while MRIs use magnetic fields and radio waves to produce detailed images of the internal structures of your body. Learn how CT scans and MRIs work, which one is safer, more painful, and more expensive, and what diseases they can diagnose. CT scans use X-rays to produce images of bones and organs, while MRIs use magnets and radio waves to produce images of soft tissues and organs.